Each year, over 1.9 million children sustain a concussion, with adolescents accounting for over 50% of these mild traumatic brain injuries. A concussion can affect cognition, concentration, processing speed, and oculomotor function. Driving requires integration of these functions, including assessment of the visual scene, processing of environmental risks, and execution of complex skills in rapid succession. Adolescents are at greatest risk for a motor vehicle crash (MVC), and the neurofunctional decrements due to concussion impairs abilities integral to safe driving. However, there are no evidence-based guidelines for return to drive recommendations for adolescents, and little research has specifically examined returning to drive after a concussion in adolescents. The long-term goal of this R01 is to establish the evidence base for return to drive recommendations for adolescents after a concussion. The objective is to examine the neurophysiological functioning of the recovering concussed adolescent brain while managing driving tasks, the association between their neurophysiological functioning and clinical assessments, and the nature of concussed adolescents' engagement in risky driving behaviors. The innovation of this R01 includes 1) Discovery, 2) Translation and 3) Real-world Assessment. In the synergy of the three Aims, this R01 will employ driving simulation, fNIRS, and pupillometry as measures of neurophysiological function; examine the association of these objective measures with clinical assessments; and prospectively quantify driving behaviors of concussed adolescents with objective on-road in-vehicle monitoring and ecological momentary monitoring (EMA) of concussion symptoms. Taken together these aims form the foundational science necessary for evidence- based recommendations for return to drive after concussion. In a driving simulated study for Aim 1 (Discovery), cognitive workload measured with functional near-infrared spectroscopy and autonomic function measured with pupillometry will be compared for concussed and non-concussed adolescents. In Aim 2 (Translation), we will evaluate the relationship between the objective measures of neurophysiology collected the simulated driving study with standard concussion assessments used in the clinical setting. In Aim 3 (Real-world Assessment), data on real-time, on-road, driving behaviors will objectively measure risky driving behaviors of concussed and non-concussed adolescents, while integrating EMA assessment of concussion symptoms. Each aim helps delineate important facets of returning to drive after concussion for adolescents, including what is happening in the concussed adolescent brain, how it relates to clinical assessments, and how concussed adolescents engage in driving behaviors that place them at most risk for an MVC. Across the three aims, this innovative approach will provide the scientific foundation to establish evidence-based clinical guidelines that can promote health and wellness as adolescents return to drive after concussion.